<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>

        console.log(Math.PI);
        console.log(Math);


       console.log(Math.floor(1.2));  // 向下
       console.log(Math.ceil(1.2));   // 向上
       console.log(Math.round(1.2));  // 四舍五入
       console.log(Math.abs(1.2));   //   绝对
       console.log(Math.random());  // 随机


       console.log(parseInt(Math.random()*10 +1));
       
       // 随机取到 x - y  之间的整数
       function get ( x , y){
           return parseInt(Math.random()*y +x)
       }

       console.log(get(5 ,90));
       
    </script>
</body>
</html>